Transparent resin composition for optical sensor filter, optical sensor, and process of producing method therefor

ABSTRACT

It is an object of the present invention to provide a highly reliable optical sensor and a production process of the same, the optical sensor being excellent in the characteristic of blocking infrared radiation and capable of being manufactured at a low cost without an increase in the number of steps carried out in the assembly of electronic apparatus. The present invention includes: a substrate  1  having an electrode  3;  a photodetector  2  electrically connected to the electrode  3;  and a light-transmissive resin encapsulating portion  11  for encapsulating the photodetector  2  on the substrate  1,  the optical sensor further including an infrared-blocking layer either inside the light-transmissive resin encapsulating portion  11  or on an outer surface of the light-transmissive resin encapsulating portion  11  for blocking infrared radiation from the outside from reaching the photodetector.

TECHNICAL FIELD

The present invention relates to an optical sensor and a process ofproducing the same. More particularly, the present invention relates toa surface-mount-type optical sensor to be used for the switching betweenon and off or adjustment of a light amount of a backlight of a liquidcrystal display such as a personal digital assistant and to a process ofproducing the optical sensor.

BACKGROUND ART

In recent years, a rapidly growing number of personal digital assistantsincluding a mobile telephone have employed a TFT color liquid crystaldisplay in their display section, and their power consumption has beenrising accordingly. For the purpose of adding the function of turningoff or down a backlight source when backlight is not needed (outdoors ona sunny day or indoors with bright illumination), surface-mount-typeoptical sensors having peak sensitivities at infrared wavelengths havecommonly been employed as a component for detecting indoor or outdoorlight.

As such an optical sensor, for example, as shown in FIGS. 24 and 25,there is known an optical sensor including, for example, a substrate101; a first metal pad 103 connected to one of terminal electrodes 104provided on a rear surface of the substrate 101; a second metal pad 103connected to the other terminal electrode 104 on the rear surface of thesubstrate 101; a photodetector 102 mounted on the first metal pad 103via a conductive adhesive 105; a small-gage metal wire 106 forelectrically connecting the photodetector 102 and the second metal pad103 together; and a resin encapsulating portion 107 made of alight-transmissive resin in substantially rectangular solid form tocover the photodetector 102 and the small-gage metal wire 106 (seeJapanese Unexamined Utility Model No. Sho 61(1986)-156250). This type ofoptical sensor, however, has a problem of malfunctioning: Where there isinvisible infrared radiation at night or indoors with weak illuminationfor some reason, the optical sensor might detect the infrared radiationto judge that the surroundings are bright.

On this account, an increasing number of optical sensors have had aninfrared-blocking filter separately provided at an upper part of theirlight-receiving portion. As an optical sensor having the function ofblocking infrared radiation, there is known the one having twophotodiodes mounted on one chip or separate chips wherein one photodiodehas a peak sensitivity at a wavelength in the visible-light region andthe other photodiode has a peak sensitivity at a wavelength in theinfrared region and wherein, on the basis of results of detections oflight by the respective photodiodes, calculation is made and it isjudged whether or not the light is in the infrared region and, if thelight is in the infrared region, the output of a detector is suspended(see Japanese Unexamined Patent Publication No. 2001-264161). In thiscase, however, a computing or amplifying function needs to be added tothe photodiodes, so that the photodiodes become special in structure andexpensive and, depending on the computational algorithm, there may becases where infrared radiation is not blocked properly.

As a visible-light sensor for detecting only visible light, opticalsensors having a photodetector encapsulated in a resin are disclosed inJapanese Unexamined Patent Publication Nos. Hei 01(1989)-266751 and Hei10(1998)-229206. In a visible-light sensor of Japanese Unexamined PatentPublication No. Hei 01(1989)-266751, a transparent resin contains glasspowders that absorb infrared radiation. In this case, however, due to asignificant difference between glass and resin in coefficient of linearexpansion, the glass powders and the resin are interspaced from eachother in a step such as heating or cooling carried out at resin molding,indicating that this sensor is not suitable for mass production. On theother hand, in resins that block infrared radiation employed in avisible-light sensor of Japanese Unexamined Patent Publication No. Hei10(1998)-229206 (the resins manufactured by Dai Nippon Toryo Co., Ltd.),their transmittances at near-infrared wavelengths ranging upwardly from700 nm are not sufficiently low as compared to peak transmittances, asshown in FIG. 26. For example, in a resin A (acrylic resin) of athickness of 2 μm, its transmittance even at a wavelength of 800 nm isas high as about one thirds of a peak transmittance, whereas even in aresin B (epoxy resin) of a thickness of 300 μm, its transmittance at awavelength of 850 nm is about one fourths of a peak transmittance.

FIGS. 5 show graphs illustrating different spectral responsecharacteristics of two types of phototransistors (Si). A phototransistorshown in FIG. 5(a) has a peak sensitivity at a wavelength of 900 nm,whereas a phototransistor shown in FIG. 5(b) has a peak sensitivity at awavelength of 650 nm. When one of the resins that blocks infraredradiation (resin A or B) is combined with the phototransistor shown inFIG. 5(a) having a peak transmittance at a wavelength of 900 nm toproduce a visible-light sensor, the sensitivity of the visible-lightsensor is in the near-infrared region of wavelengths of 800 nm to 900nm. Even when one of the resins that blocks infrared radiation (resin Aor B) is combined with the phototransistor shown in FIG. 5(b) having apeak transmittance at a wavelength of 650 nm to produce a visible-lightsensor, the sensitivity of the visible-light sensor at near-infraredwavelengths ranging upwardly from 700 nm is not sufficiently low. Thus,use of these visible-light sensors is impractical.

DISCLOSURE OF INVENTION

Under these circumstances, according to the present invention, there isprovided an optical sensor (A) comprising: a substrate having anelectrode; a photodetector electrically connected to the electrode; anda light-transmissive resin encapsulating portion for encapsulating thephotodetector on the substrate, the optical sensor characterized byfurther comprising an infrared-blocking layer either inside thelight-transmissive resin encapsulating portion or on an outer surface ofthe light-transmissive resin encapsulating portion for blocking infraredradiation from the outside from reaching the photodetector.

Also, according to the present invention, there is provided an opticalsensor (B) comprising: a substrate having an electrode; a photodetectorelectrically connected to the electrode; and a light-transmissive resinencapsulating portion for encapsulating the photodetector on thesubstrate, the optical sensor characterized in that thelight-transmissive resin encapsulating portion contains aninfrared-absorbing substance. That is, the light-transmissive resinencapsulating portion is formed of a light-transmissive resin containingthe infrared-absorbing substance, so that the light-transmissive resinencapsulating portion itself has the function of absorbing infraredradiation.

The optical sensors (A) and (B) thus constituted have the function ofabsorbing or reflecting light in the infrared region incorporatedtherein without an increase in the number of components and with asimple constitution. Thus, it is possible to save time and effort toincorporate an infrared-blocking filter, separately from the opticalsensor, into electronic equipment such as a personal digital assistant,so that the electronic equipment can be manufactured at a low costwithout an increase in the number of assembly steps. Further, accordingto the optical sensor (B), the light-transmissive resin encapsulatingportion having the function of absorbing infrared radiation can beformed by one molding step, resulting in efficient manufacturing of theoptical sensor without an increase in the number of manufacturing steps.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view showing an optical sensor according toEmbodiment 1 of the present invention;

FIG. 2 is a front view in section showing the optical sensor accordingto Embodiment 1;

FIGS. 3(a) to (e) are graphs showing relationships infrared-absorbingdyes have between an absorption peak sensitivity and a spectraltransmittance;

FIGS. 4(a) and (b) are graphs showing simulation results wheninfrared-absorbing dyes are blended;

FIGS. 5(a) and (b) are graphs showing different spectral responsecharacteristics of two types of Si phototransistors;

FIGS. 6(a) and (b) are graphs showing the spectral responses andinfrared-absorbing dye simulations, of the phototransistors;

FIGS. 7(a) to (g) are a flowchart showing the step of forming a resinencapsulating portion in the production of the optical sensor accordingto Embodiment 1;

FIG. 8 is a partial plan view showing one example of an electrodepattern to be used in the production of the optical sensor according toEmbodiment 1;

FIG. 9 is a perspective view showing an optical sensor according toEmbodiment 2 of the present invention;

FIG. 10 is a front view in section showing the optical sensor accordingto Embodiment 2;

FIGS. 11(a) to (d) are a flowchart showing the step of forming a resinencapsulating portion in the production of the optical sensor accordingto Embodiment 2;

FIGS. 12(a) to (d) are a flowchart showing the step of forming a resinencapsulating portion in the production of an optical sensor accordingto Embodiment 3;

FIG. 13 is a front view in section showing an optical sensor accordingto Embodiment 4 of the present invention;

FIGS. 14(a) to (d) are a flowchart showing the step of forming a resinencapsulating portion in the production of the optical sensor accordingto Embodiment 4;

FIG. 15 is a front view in section showing an optical sensor accordingto Embodiment 5 of the present invention;

FIGS. 16(a) to (d) are a flowchart showing the step of forming a resinencapsulating portion in the production of the optical sensor accordingto Embodiment 5;

FIG. 17 is a front view in section showing an optical sensor accordingto Embodiment 6 of the present invention;

FIGS. 18(a) to (e) are a flowchart showing the step of forming a resinencapsulating portion in the production of the optical sensor accordingto Embodiment 6;

FIG. 19 is a front view in section showing an optical sensor accordingto Embodiment 7 of the present invention;

FIGS. 20(a) to (c) are a flowchart showing the step of forming a resinencapsulating portion in the production of the optical sensor accordingto Embodiment 7;

FIG. 21 is a front view in section showing an optical sensor accordingto Embodiment 8 of the present invention;

FIGS. 22(a) to (c) are a flowchart showing the step of forming a resinencapsulating portion in the production of the optical sensor accordingto Embodiment 8;

FIGS. 23(a) to (d) are a flowchart showing the step of forming a resinencapsulating portion in another process of producing the optical sensoraccording to Embodiment 8;

FIG. 24 is a perspective view showing a conventional optical sensor;

FIG. 25 is a front view in section showing the conventional opticalsensor; and

FIG. 26 is a graph showing a characteristic of a resin that blocksinfrared radiation and that is used in another conventional opticalsensor.

BEST MODE FOR CARRYING OUT THE INVENTION

In the optical sensor (A) according to the present invention, theinfrared-blocking layer is a layer that allows light in thevisible-light region (about 380 nm to 800 nm) to transmit through it andthat allows light in the infrared region (about 800 nm to 10000 nm) tobe absorbed in or reflected from it. More specifically, theinfrared-blocking layer is made of either an infrared-absorbing layercontaining an infrared-absorbing substance or an infrared-reflectinglayer containing an infrared-reflecting substance.

The infrared-absorbing layer containing the infrared-absorbing substancemay be either an infrared-absorbing film of a transparent resincontaining the infrared-absorbing substance or a transparent resin layercontaining the infrared-absorbing substance. The infrared-absorbingsubstance is suitably a phthalocyanine compound described in JapaneseUnexamined Patent Publication No. 2001-106689 represented by the generalformula (I):

wherein Zi (i=1-16) is SR₁, OR₂, NHR₃ or a halogen atom, wherein R₁, R₂and R₃ are a phenyl group which may have substituent(s), an aralkylgroup which may have substituent(s) or a C₁-C₂₀ alkyl group which mayhave substituent(s); and M is a nonmetal, a metal, a metallic oxide or ametallic halide. Preferably, two or more of infrared-absorbing dyeshaving different characteristics are used in optimized combination toobtain the target characteristic of blocking infrared radiation in awide range, resulting in an improved reliability of the optical sensor.In this case, depending on the target characteristic of blockinginfrared radiation, an infrared-absorbing dye may be added in an amountof 0.1 wt % to 1.0 wt % with respect to 100 wt % of the transparentresin. When the infrared-absorbing dye is added in an amount of lessthan 0.1 wt % of with respect to 100 wt % of the transparent resin, thesensitivity rises but the infrared blockage effect is reduced. On theother hand, when infrared radiation dye is added in an amount of morethan 1.0 wt %, the infrared blockage effect is improved but thesensitivity lessens.

The infrared-reflecting layer containing the infrared-reflectingsubstance may be either an infrared-reflecting multilayer film wherein aphase difference between wavelengths is utilized or a transparent resinlayer or film containing the infrared-reflecting substance. Examples ofinfrared-reflecting substances include titanium dioxide, silicon dioxideand the like. Preferably, two or more of infrared-reflecting substancesare used in optimized combination.

In the optical sensor (A) according to the present invention, thelight-transmissive resin encapsulating portion may have an inner resinportion for encapsulating the photodetector and an outer resin portionfor covering the inner resin portion. The infrared-blocking layer may bemade of either an infrared-absorbing layer containing theinfrared-absorbing substance or an infrared-reflecting layer containingthe infrared-reflecting substance, which is interposed between the innerresin portion and the outer resin portion. When the infrared-blockinglayer is formed inside the transparent resin encapsulating portionhaving a double-layer structure, the infrared-blocking layer can easilyentirely cover the photodetector, resulting in an improvedcharacteristic of blocking infrared radiation.

In the sensor (B) according to the present invention, theinfrared-absorbing substance is suitably the phthalocyanine compound ofthe general formula (I). More specifically, two or more ofinfrared-absorbing dyes having different characteristics are preferablyused in optimized combination to obtain the target characteristic ofblocking infrared radiation in a wide range, resulting in a greatlyimproved reliability of the optical sensor. In this case, depending onthe target characteristic of blocking infrared radiation, theinfrared-absorbing dye may be added in an amount of 0.1 wt % to 1.0 wt %with respect to 100 wt % of the transparent resin. When theinfrared-absorbing dye is added in an amount of less than 0.1 wt % withrespect to 100 wt % of the transparent resin, the sensitivity rises butthe infrared blockage effect is reduced. On the other hand, when theinfrared-absorbing dye is added in an amount of more than 1.0 wt %, theinfrared blockage effect is improved but the sensitivity lessens.

As described above, when the phthalocyanine-based dye represented by thegeneral formula (I) which is an organic material is used as aninfrared-absorbing material, the light-transmissive resin encapsulatingportion can be formed by an ordinary resin-molding technique despite thefact that the light-transmissive resin (molded resin) contains theinfrared-absorbing material. Thus, the present invention can realize thevisible-light sensor capable of being down-sized and easilymass-produced.

The phthalocyanine compound may be prepared by the process described inJapanese Unexamined Patent Publication No. 2001-106689. In thepreparation, M or Z in the above general formula (I) may be changed soas to adjust the wavelength at which the phthalocyanine compound has anabsorption peak.

In the phthalocyanine compound represented by the general formula (I),examples of substituents optionally contained in a phenyl group or anaralkyl group include halogen atom, acyl, alkyl, phenyl, alkoxyl, alkylhalide, alkoxyl halide, nitro, amino, alkylamino, alkylcarbonylamino,arylamino, arylcarbonylamino, carbonyl, alkoxycarbonyl,alkylaminocarbonyl, alkoxysulfonyl, alkylthio, carbamoyl,aryloxycarbonyl, oxyalkylether and cyano groups and the like. The numberof the substituents is suitably one to three.

In the phthalocyanine compound represented by the general formula (I),examples of unsubstituted C₁₋₂₀ alkyl groups include linear, branchedand cyclic alkyl groups, among which linear, branched and cyclic C₁₋₈alkyl groups are preferable. Specific examples of unsubstituted C₁₋₈alkyl groups include methyl, ethyl, n-propyl, isopropyl, n-butyl,isobutyl, sec-butyl, tert-butyl, n-pentyl, isopentyl and neopentylgroups and the like, among which methyl, ethyl, n-propyl, isopropyl andn-butyl groups are preferable. Examples of substituents optionallycontained in a C₁₋₂₀ alkyl group include a halogen atom, alkoxyl,hydroxyalkoxyl, alkoxyalkoxyl, alkoxyl halide, nitro, amino andalkylamino groups and the like. The number of the substituents issuitably one to two.

In the phthalocyanine represented by the general formula (I), examplesof halogen atoms include a fluorine, chlorine, bromine and iodine atoms,among which a chlorine atom is preferable.

In the phthalocyanine compound represented by the general formula (I),the nonmetal is any atom other than a metal atom and may be two hydrogenatoms. Examples of metals include iron, magnesium, nickel, cobalt,copper, palladium, zinc, vanadium, titanium, indium, tin and the like.Examples of metallic oxides include titanyl, vanadyl and the like.Examples of metallic halides include aluminum chloride, indium chloride,germanium chloride, tin chloride (II), tin chloride (IV), siliconchloride and the like. Preferably, a metal, metallic oxide or metallichalide is adopted. Specific examples include copper, zinc, cobalt,nickel, iron, vanadyl, titanyl, indium chloride and tin chloride (II),among which copper, vanadyl and zinc are preferable.

According to the present invention, the phthalocyanine compoundrepresented by the general formula (I) is preferably a phthalocyaninecompound having an absorption peak in the range of wavelengths of 750 nmto 1000 nm. More specifically, a combination of two or more selectedfrom five phthalocyanine compounds having absorption peaks atwavelengths in the vicinity of 750 nm, 800 nm, 900 nm, 950 nm and 1000nm, respectively, are preferable. For the purpose of blocking light inthe infrared region in actual use, a combination of about fourphthalocyanine compounds having absorption peaks in the range ofwavelengths 800 nm to more are preferable. For the purpose of blockinglight in the near-infrared region as well, a combination of about fivephthalocyanine compounds including one having an absorption peak at awavelength of 750 nm are more preferable. The proportion of eachphthalocyanine compound is not particularly limited. When it is intendedto evenly block light in the infrared region, the phthalocyaninecompounds may be used in equivalent amounts, whereas when it is intendedto block light having a particular wavelength, a phthalocyaninecompounds having an absorption peak at the particular wavelength may beincluded among them in an increased amount.

The optical sensors (A) and (B) according to the present invention mayfurther include a light-shielding frame that covers all the outersurfaces of the light-transmissive resin encapsulating portion except anouter surface on the side of a light-receiving surface of thephotodetector. With the present invention constituted as above, thelight-shielding frame covers all the side surfaces of the photodetectorexcept the light-receiving surface thereof so that all light that entersthe photodetector passes through the infrared-absorbing layer, resultingin an improved characteristic of blocking infrared radiation.

The transmittance of the light-transmissive resin encapsulating portionin the visible-light region may be substantially constant in the rangeof blue light (450 nm) to red light (650 nm). By being constituted asabove, the present invention can realize the optical sensor showing thedependence on wavelength.

Also, in the optical sensors (A) and (B), as described above, it ispreferable to employ two or more infrared-absorbing substances havingabsorption peaks at different wavelengths to obtain a characteristic oftransmittance substantially flat in the visible-light region. Morespecifically, when the phthalocyanine compound having an absorption peakin the range of wavelengths of 750 nm to 1000 nm is used, the presentinvention can provide the optical sensor having a characteristic closerto the visibility of the human eye.

When a plurality of phthalocyanine dyes having absorption peaks atdifferent wavelengths are used in combination with a sensitivitycharacteristic of a phototransistor (photodetector), the presentinvention can realize the optical sensor having a characteristic closerto the visibility of the human eye. Such an optical sensor has theadvantage as follows. It can also be used, for example, for monitoringbrightness and color shade of a white light source of a liquid-crystalbacklight device or the like purpose. More specifically, when asemiconductor light-emitting device is used as a light source, thelight-emission efficiency changes with time, and the output from thelight-emitting device needs to be monitored to adjust the drive voltagethereof. More specifically, when a red semiconductor light-emittingdevice, a green semiconductor light-emitting device and a bluesemiconductor light-emitting device are used to perform full-colordisplay as in the liquid-crystal backlight device, such a problem comesup that the color shade changes as the light-emission intensity changesfrom its original state. When the visible-light sensor as describedabove is used as the optical sensor, the changes in shade can bemonitored in the state as viewed by the human.

In the optical sensor according to the present invention, thephotodetector is not particularly limited and may be, for example, aphototransistor, a photodiode or the like. More specifically, aphotodetector having a peak sensitivity to light in the visible-lightregion is preferable, and for example, a Si phototransistor ispreferable. As described above, the optical sensor of the presentinvention wherein the photodetector has a characteristic close to thevisibility of the human eye has the advantage of being closer to thehuman vision.

According to the present invention, there is provided a process ofproducing the optical sensor (A), comprising the steps of: electricallyconnecting a photodetector to an electrode provided on a substrate; andforming a light-transmissive resin encapsulating portion on thesubstrate so that the photodetector is entirely encapsulated in thelight-transmissive resin encapsulating portion, wherein the step offorming the light-transmissive resin encapsulating portion includes thestep of forming an infrared-blocking layer either inside thelight-transmissive resin encapsulating portion or on an outer surface ofthe light-transmissive resin encapsulating portion for blocking infraredradiation from the outside from reaching the photodetector.

According to the present invention, there is provided a process ofproducing the optical sensor (B), comprising the steps of: electricallyconnecting a photodetector to an electrode provided on a substrate; andforming a light-transmissive resin encapsulating portion on thesubstrate so that the photodetector is entirely encapsulated in thelight-transmissive resin encapsulating portion, wherein in the step offorming the light-transmissive resin encapsulating portion, thelight-transmissive resin encapsulating portion is formed of a tranparentresin containing an infrared-absorbing substance.

According to the process of producing the optical sensor (A) and theprocess of producing the optical sensor (B) of the present invention,the optical sensors (A) and (B) having improved characteristics caneasily be produced at a low cost.

In the process of producing the optical sensor (A), the step of formingthe infrared-blocking layer may include forming, on the outer surface ofthe light-transmissive resin encapsulating portion, either aninfrared-absorbing layer containing an infrared-absorbing substance oran infrared-reflecting layer containing an infrared-reflectingsubstance. With this arrangement, the infrared-reflecting layer caneasily be formed after the light-transmissive resin encapsulatingportion is formed.

Also, in the process of producing the optical sensor (A), the step offorming the resin encapsulating portion may include the steps of:forming an inner resin portion for encapsulating the photodetector;forming the infrared-blocking layer for covering an outer surface of theinner resin portion with either an infrared-absorbing layer containingan infrared-absorbing substance or an infrared-reflecting layercontaining an infrared-reflecting substance; and forming an outer resinportion for covering an outer surface of either the infrared-absorbinglayer or the infrared-reflecting layer.

With this arrangement, the infrared-absorbing layer or theinfrared-reflecting layer covers not only the light-receiving surface(upper surface) of the photodetector but also the side surfaces thereof,so that infrared radiation from the side surfaces of the transparentresin encapsulating portion can be blocked, resulting in an improvedcharacteristic of blocking infrared radiation.

The process of producing the optical sensor (A) and the process ofproducing the optical sensor (B) according to the present invention mayfurther comprise the step of forming a light-shielding frame forcovering all the outer surface of the light-transmissive resinencapsulating portion except an outer surface thereof on alight-receiving surface side of the photodetector, the step of formingthe light-shielding frame being carried out before the step of formingthe resin encapsulating portion. With this arrangement, thelight-shielding frame prevents light from reaching all the surfaces ofthe photodetector except the light-receiving surface thereof, so thatall light to enter the photodetector is blocked by either the infraredradiation absorbing layer or the infrared radiation reflecting layer,resulting in an improved characteristic of blocking infrared radiation.

Also, the step of forming the resin encapsulating portion may comprise:holding the substrate, having a plurality of said photodetectors mountedthereon, between an upper mold and a lower mold, the upper mold having,in correspondence with the photodetectors, a plurality of recesses to beused for formation of the light-transmissive resin encapsulatingportion; pouring a light-transmissive resin into the recesses inside themold; and then curing the resin thereby to form the resin encapsulatingportions. With this arrangement, the optical sensors excellent incharacteristic of blocking infrared radiation can be mass-produced.

In another aspect, the present invention provides a light-transmissiveresin composition to be used both for an optical sensor filter and forencapsulating a photodetector of an optical sensor, thelight-transmissive resin composition having an infrared radiationblockage function provided by addition of a plurality of phthalocyaninedyes as infrared-absorbing substances to a light-transmissive resin.

Hereinafter, specific embodiments of the present invention will beexplained in detail with reference to the drawings. However, the presentinvention is not limited to these embodiments.

EMBODIMENT 1

FIG. 1 is a perspective view showing an optical sensor according toEmbodiment 1 of the present invention; and FIG. 2 is a front view insection showing the optical sensor according to Embodiment 1.

An optical sensor 10 according to Embodiment 1 includes: a substrate 1having, on a mounting surface thereof, a pair of electrodes (metal padportions) 3 of opposite polarity; a photodetector 2 electricallyconnected to the electrodes 3 on the substrate 1; and alight-transmissive resin encapsulating portion 11 for encapsulating thephotodetector 2 on the substrate 1; and an infrared-absorbing layer 12formed on an outer surface of the light-transmissive resin encapsulatingportion 11, the infrared-absorbing layer 12 serving as aninfrared-blocking layer that is.

The substrate 1 is made of, for example, glass or an epoxy resin, andshaped in a rectangular plate. The pair of electrodes 3,3 are ofopposite polarity and formed at the opposite sides on a mounting surfaceof the substrate 1. On the substrate 1, there are also formed a pair ofterminal electrodes 4,4 joined to the pair of electrodes 3,3,respectively, and extending along the opposite side surfaces of thesubstrate 1 and further along a rear surface thereof.

The photodetector 2 is shaped in a rectangular block and is, forexample, a phototransistor, a pliotodiode or the like. The photodetector2 has an electrode portion on a light-receiving surface 2 a side andanother electrode portion on the side opposite to the light-receivingsurface 2 a. The electrode portion on the side opposite to thelight-receiving surface 2 a is electrically connected via a conductiveadhesive 5 to one of the electrodes 3 on the substrate 1. The electrodeportion on the light-receiving surface 2 a side is electricallyconnected via a small-gage metal wire 6 to the other electrode 3 on thesubstrate 1.

The photodetector 2 to be used in the present invention is notparticularly limited, may be a phototransistor, a photodiode or the likeas described above, and is preferably, a Si phototransistor, a Siphotodiode or the like, having a peak sensitivity in the visible-lightregion. This will be explained later.

The light-transmissive resin encapsulating portion 11 is made of, forexample, an epoxy resin having insulating, light-transmissive andthermosetting properties, shaped in a substantially rectangular solid,and covers the photodetector 2 and the small-gage metal wire 6.

The infrared-absorbing layer 12 for blocking infrared radiation from theoutside from reaching the photodetector is made of an infrared-absorbingfilm and bonded to an upper surface of the light-transmissive resinencapsulating portion 11 by means of a transparent adhesive. Theinfrared-absorbing film is obtained by forming a transparent resin(e.g., epoxy resin) containing, for example, infrared-absorbingsubstances into a film having a thickness of 20 μm to 100 μm.

As the infrared-absorbing substances, two or more infrared-absorbingdyes having different absorption peak sensitivities and spectraltransmittances are used in combination since it is difficult to block(absorb) infrared radiation in a wide range by the use of only oneinfrared-absorbing dye. By the optimal use of a number ofinfrared-absorbing dyes having different absorption peak sensitivitiesand spectral transmittances, the target characteristic of blockinginfrared radiation in a wide range can be obtained.

An explanation will be given taking, for example, fourinfrared-absorbing dyes having absorption peaks at differentwavelengths.

FIGS. 3 are graphs showing relationships the infrared-absorbing dyeshave between an absorption peak sensitivity and a spectraltransmittance. FIG. 3(a) is a graph of an infrared-absorbing dye A; FIG.3(b) is a graph of an infrared-absorbing dye B; FIG. 3(c) is a graph ofan infrared-absorbing dye C; and FIG. 3(d) is a graph of aninfrared-absorbing dye D. These graphs show that the infrared-absorbingdyes A, B, C and D have absorption peaks at wavelengths in the vicinityof 800 nm, 900 nm, 950 nm, 1000 nm, respectively.

For example, when it is intended to block infrared radiation havingwavelengths longer than 800 nm, the infrared-absorbing dyes A, B, C andD are used together in optimal proportions to make substantiallyconstant the transmittance in the range of the wavelengths of 450 nm to650 nm as shown by the simulation result in FIG. 4(a). When alight-transmissive resin containing these infrared-absorbing substancesis used to encapsulate photodetectors made of Si phototransistors havingphototransistor spectral response characteristics shown in FIGS. 5(a)and 5(b), optical sensors showing the dependences of sensitivity onwavelength as shown in FIGS. 6(a) and 6(b) can be obtained. That is, thesimulation result obtained when a conventional photodetector of FIG.5(a) is used is shown in FIG. 6(a). The peak sensitivity wavelength is650 nm and thus slightly longer than the wavelength of 555 nm at whichthe peak of the visibility is located, though the sensitivity at awavelength of 800 nm is less than 30% of the sensitivity at the peakwavelength, which means that the optical sensor of FIG. 6(a) can blockinfrared radiation to a certain extent. Also, the optical sensor of FIG.6(a), which employs the phototransistor of FIG. 5(a) having a peaksensitivity at a wavelength of 900 nm, shows a rise in the transmittancein the range of wavelengths of 1000 nm to longer (has a small peak insensitivity at 1050 nm). The rise, however, does not constitute anyproblem in actual use of the optical sensor because the Siphototransistor does not have any sensitivity to light in the aboverange of wavelengths. In the optical sensor of FIG. 6(b), on the otherhand, the sensitivity at a wavelength of 800 nm is lower, that is, lessthan 10% of the sensitivity at the peak wavelength, which means that theoptical sensor of FIG. 6(b) can block, at an increased rate, infraredradiation in the range of wavelengths of 800 nm to longer.

FIG. 6(e) shows another case. FIG. 6(e) is a graph of aninfrared-absorbing dye E having an absorption peak at a wavelength of750 nm. When the infrared-absorbing dyes A to E are used together inoptimal proportions, the simulation result shown in FIG. 4(b) can beobtained.

Comparison between the simulation results of FIGS. 4(a) and 4(b)indicates that, in both the simulation results, the transmittance issubstantially constant in the range of wavelengths of 450 nm to 650 nm.In the simulation result of FIG. 4(b), on the other hand, thetransmittance of infrared radiation having wavelengths longer than 750nm is substantially 20% or less of the peak, which means that when theinfrared-absorbing dyes A to E are used together in optimal proportions,the optical sensor has a characteristic closer to the visibility of thehuman eye.

The optical sensor according to Embodiment 1 employs as theinfrared-absorbing substances the phthalocyanine-based dyes, which areorganic dyes, so that it is ensured that the light-transmissive resinthat contains the phthalocyanine-based dyes and that constitutes theinfrared-absorbing layer 12 is substantially the same in linearexpansion coefficient as the molding resin that constitutes thelight-transmissive resin encapsulating portion 11. Therefore, aconventional resin-molding technique can be employed in the productionof the optical sensor of Embodiment 1.

Next, an explanation will be given on a peak sensitivity of thephotodetector 2. FIGS. 5 are graphs showing different spectral responsecharacteristics of two Si phototransistors. When a peak sensitivity anda spectral response characteristic of the optical sensor of Embodiment 1are close to the characteristics of the visible light, especially to thecharacteristics of the human eye visibility, and thus the vision of theoptical sensor is closer to the human vision, the optical sensor becomesan effective device in blocking infrared radiation. Because typicalphotodetectors are used in combination with infrared radiation (aninfrared LED), many have a peak sensitivity at a wavelength of about 900nm. One example is a photodetector (phototransistor) having a spectralresponse characteristic as shown in FIG. 5(a). An optical sensor of thetype that detects light in the environment, for example, solar radiationand light from lighting fixtures such as a fluorescent lamp and a lightbulb is suitably a photodetector having a sensitivity to visible light(about 380 nm to 800 nm). One preferable example is a photodetector(phototransistor) having a spectral response characteristic: the peaksensitivity is at a wavelength of about 650 nm, as shown in FIG. 5(b). Aphotodetector suitable for blocking infrared radiation is again thephotodetector having a peak sensitivity in the visible-light region.When employing the photodetector having a peak sensitivity at awavelength of about 650 nm as shown in the simulation result on thespectral response characteristic in FIG. 6(b), the optical sensor has animproved characteristic of blocking infrared radiation.

As well known, the phototransistor as described above can be realized bychanging the depth of a pn junction created by diffusing B (boron) orthe like in an n-type Si semiconductor substrate. When the depth ofdiffusion is sufficiently great, the photodetector obtained has awavelength sensitivity upon which the absorption characteristic of Si isreflected as shown in FIG. 5(a). As the depth of diffusion is madeshallower, the photodetector obtained has a peak sensitivity shiftedtoward the visible-light region as shown in FIG. 5(b). When the depth ofdiffusion is made too shallow, however, the withstand voltage is reducedto make the use of the optical sensor impractical. Currently, the limitof the peak sensitivity wavelength is about 650 nm as shown in FIG.5(b).

Next, with reference to FIGS. 7 and 8, there will be explained a processof producing the optical sensor 10 of Embodiment 1 which has beenexplained with reference to FIGS. 1 and 2. FIGS. 7 are a flowchartshowing the step of forming the resin encapsulating portion in theproduction of the optical sensor of Embodiment 1; and FIG. 8 is apartial plan view showing one example of an electrode (metal wiring)pattern to be used in the production of the optical sensor of Embodiment1.

The process of producing the optical sensor of Embodiment 1 includes thesteps of: electrically connecting the photodetector 2 to the electrode 3provide on the substrate 1; and forming the light-transmissive resinencapsulating portion 11 on the substrate 1 so that thelight-transmissive resin encapsulating portion 11 entirely encapsulatesthe photodetector 2. In the step of electrically connecting thephotodetector to the electrodes, a plurality of said photodetectors 2are mounted, via the conductive adhesive 5, on the electrodes 3 arrangedin an electrode pattern 7 as shown in FIG. 8, and are electricallyconnected to the electrodes 3. Detailed explanations are omitted sincethis step is carried out by the same known technique as employedconventionally. The electrode pattern 7 shown in FIG. 8 is merely anexample, and the wiring pattern may be designed arbitrarily so that itdoes not interfere with the steps to be carried out later.

FIG. 7(a) shows a state wherein the plurality of photodetectors 2 aremounted on the electrodes on the substrate 1 and electrically connectedthereto. In the step of forming the light-transmissive resinencapsulating portion, first., as shown in FIG. 7(b), the substrate 1,having the plurality of photodetectors 2 mounted thereon, is set in alower mold 8, then as shown in FIG. 7(c), the substrate 1 is held andfixed between an upper mold 9 and the lower mold 8 under conditionswhere no resin leakage, substrate fracture or the like will occur, and aresin is transfer-molded under heating at about 150° C. The upper mold 9has, in a lower surface thereof, substantially rectangular recesses tobe used for formation of the encapsulating portions. However, since theshape of the recess decides the shape of the encapsulating portion, therecess may be designed arbitrarily as long as the recess allows theencapsulating portion to have a flat upper surface. When the molds areseparated from each other after the resin is cured, it is found that asshown in FIG. 7(d), the photodetectors 2 and the small-gage metal wires6 on the substrate 1 are encapsulated in the transparent resinencapsulating portions 11.

Next, in the step of forming the resin encapsulating portion, theinfrared-absorbing layer 12 for blocking infrared radiation from theoutside from reaching the photodetector 2 is formed on an outer surfaceof the light-transmissive resin encapsulating portion 11. Morespecifically, as shown in FIG. 7(e), a light-transmissive adhesive 14 isapplied by using a dispenser 13 or the like to the upper surface of thetransparent resin encapsulating portion 11, and then, as shown in FIG.7(f), the infrared-absorbing film serving as the infrared-absorbinglayer 12 is bonded to the upper surface of the transparent resinencapsulating portion. Thus, there is obtained a molded resin parthaving the infrared-absorbing layer 12 on the upper surface of thelight-transmissive resin encapsulating portion 11. After that, thesubstrate is sectioned using a dicing blade or the like to separate themolded resin parts from one another on a product-by-product basis. Thus,the individual optical sensors are completed as products.

In the optical sensor 10 according to Embodiment 1, the product has thefunction of absorbing infrared radiation incorporated therein, so thatit is possible to save time and effort to incorporate aninfrared-blocking filter separately from the optical sensor. Also, byusing the photodetector 2 having a peak sensitivity in the visible-lightregion, control can be made on a criterion closer to the one applied bythe human eye. Also, in the process of producing the optical sensor 10according to the present invention, only by adding the step of bondingthe infrared-absorbing film serving as the infrared-absorbing layer 12to the upper surface of the transparent resin encapsulating portion 11,it is possible to easily produce the optical sensor having the infraredradiation blockage function.

EMBODIMENT 2

FIG. 9 is a perspective view of an optical sensor according toEmbodiment 2 of the present invention; and FIG. 10 is a front view insection showing the optical sensor according to Embodiment 2.

In an optical sensor 20 according to Embodiment 2, a light-transmissiveresin encapsulating portion 21 has an inner resin portion 22 and anouter resin portion 23, the inner resin portion 22 encapsulating thephotodetector 2, the outer resin portion 23 covering the inner resinportion 22. The infrared-absorbing layer 12 is made of aninfrared-absorbing film interposed between the inner resin portion 22and the outer resin portion 23. Like reference numerals denote likeparts in Embodiment 1 and explanations thereon are omitted.

The inner resin portion 22 is made of, for example, an epoxy resinhaving insulating, light-transmissive and thermosetting properties. Theouter resin portion 23 is made of, for example, an epoxy resin havinglight-transmissive and thermosetting properties. The inner resin portion22 and outer resin portion 23 may be made of the same or differentresins.

A process of producing the optical sensor 20 of Embodiment 2 will beexplained with reference to a flowchart of FIG. 11 showing the step offorming the resin encapsulating portion in the production of the opticalsensor.

In the step of forming the resin encapsulating portion according toEmbodiment 2, first, there is carried out as shown in FIG. 11(a) thestep of forming the inner resin portions on the substrate 1, having theplurality of photodetectors 2 mounted thereon, so that the inner resinportions 22 cover the photodetectors 2, respectively. The step offorming the inner resin portions is carried out in the same manner as inEmbodiment 1 shown in FIGS. 7(a) to 7(c). Next, as shown in FIG. 11(b),the substrate 1 is set in a lower mold 91, then aninfrared-absorbing-layer formation film 12′ is placed on the inner resinportion 22 on the substrate 1, and then a sheet resin 23′ of B stagetype, a type of resin having a high light-transmittance and having beencured midway, is placed on the infrared-absorbing-layer formation film12′. After that, hot pressing with an upper mold 92 and the lower mold91 is carried out, as shown in FIG. 11(c). Thus, there is obtained amolded resin part wherein all the outer surfaces of each inner resinportion 22 are covered with the infrared-absorbing layer 12 and whereinall the outer surfaces of the infrared-absorbing layer 12 are coveredwith the outer resin portion 23, as shown in FIG. 11(d). After that, thesubstrate is sectioned using the dicing blade or the like to separatethe molded resin parts from one another on a product-by-product basis.Thus, the individual optical sensors 20 are completed as products.

In the optical sensor 20 according to Embodiment 2, not only thelight-receiving surface (upper surface) of the photodetector 2 but alsothe side surfaces thereof are covered with the infrared-absorbing layer12, so that infrared radiation to enter the transparent resinencapsulating portion 21 also from the side surfaces thereof can beblocked. Thus, the optical sensor has an improved characteristic ofblocking infrared radiation in addition to the same effect as obtainedin Embodiment 1. In the process of producing the optical sensor 20, theinfrared-absorbing layer 12 and the outer resin portion 23 can be formedin one step efficiently.

EMBODIMENT 3

FIGS. 12 are a flowchart showing the step of forming the resinencapsulating portions in the production of an optical sensor accordingto Embodiment 3 of the present invention.

In the optical sensor according to Embodiment 3, a transparent adhesivelayer 24 is interposed between the transparent resin encapsulatingportion 21 and the infrared-absorbing layer 12, of Embodiment 2. Aprocess of producing the optical sensor according to Embodiment 3 willbe explained as follows. In the step of forming the resin encapsulatingportion, the substrate 1 on which as shown in FIG. 12(a), the innerresin portions 22 are mounted to cover the plurality of photodetectors2, respectively, is set in the lower mold 91, as shown in FIG. 12(b).Next, a transparent-adhesive-layer formation film 24′ having heatresistance is placed on the inner resin portions 22 on the substrate 1,then the infrared-absorbing-layer formation film 12′ is placed on thetransparent-adhesive-layer formation film 24′ having heat resistance,and the sheet resin 23′ of B stage type, a type of resin having a highlight-transmittance and having been cured midway, is placed on theinfrared-absorbing-layer formation film 12′. After that, hot pressingwith an upper mold 92 and the lower mold 91 is carried out, as shown inFIG. 12(c). Thus, there is obtained a molded resin part wherein all theouter surfaces of the inner resin portion 22 are covered with theinfrared-absorbing layer 12 and wherein all the outer surfaces of theinfrared-absorbing layer 12 are covered with the outer resin portion 23,as shown in FIG. 12(d). After that, the substrate is sectioned using adicing blade or the like, in the same manner as described above. Thus,the individual optical sensors are completed as products.

With the optical sensor constituted as above, an improved contact isestablished between the inner resin portion 22 and theinfrared-absorbing layer 12.

EMBODIMENT 4

FIG. 13 is a front view in section of an optical sensor according toEmbodiment 4 of the present invention; and FIGS. 14 are a flowchartshowing the step of forming the resin encapsulating portion in theproduction of the optical sensor according to Embodiment 4.

In the optical sensor according to Embodiment 4, a light-transmissiveresin encapsulating portion 41 contains infrared-absorbing substances.Like reference numerals denote like parts in Embodiment 1 andexplanations thereon are omitted.

The light-transmissive resin encapsulating portion 31 contains a mixtureof predetermined amounts of two or more infrared-absorbing dyes and aresin (e.g., epoxy resin) having insulating, light-transmissive andthermosetting properties.

There will be explained the transparent resin encapsulating portion 41having the function of absorbing infrared radiation.

Table 1 shows the results of measurements on the characteristics of anoptical sensor obtained by varying the proportion of theinfrared-absorbing dyes to the transparent resin in stages in the rangeof 0 wt % to 0.1 wt %. The results in Table 1 are experimental resultsobtained on the product of a large size (3.5 mm×2.8 mm×1.9 mm(thickness)). It is necessary to vary the proportion depending on theproduct size. The proportion, in the case where only oneinfrared-absorbing dye is used, refers to the proportion of the oneinfrared-absorbing dye to the light-transmissive resin, while in thecase of a plurality of dyes are used, the proportion refers to theproportion of all the dyes to the transparent resin. TABLE 1Relationship between Amount of Infrared-Absorbing Dyes to be Added andCharacteristics of Optical Sensor Peak Amount of Dyes Light Wavelengthof to be Added Photocurrent Transmittance Light Receiving (wt %) (μA)(%) Sensitivity (nm) 0 1.796 66.7 590 0.10 0.951 47.6 590 0.30 0.47130.5 580 0.40 0.268 18.5 570 1.00 0.138 8.5 570

As seen from Table 1, as the proportion of the infrared-absorbing dyesis raised (the amount of the dyes to be added is increased), thetransmittance declines, the photocurrent output from the optical sensordecreases, and the light receiving sensitivity of the optical sensorlessens. On the other hand, the rate of blockage of infrared radiationhaving a wavelength of 770 nm, slightly shorter than 800 nm, increasesas the proportion of the infrared-absorbing dye(s) is raised. Thisindicates that the absorption by the dyes is not saturated in the aboverange of proportions. Also, the transmittance slightly changes. As theproportion of the dyes to be added is increased, the peak wavelength oflight receiving sensitivity shortens, i.e., the peak shifts toward awavelength of 550 nm, a desirable peak wavelength.

Accordingly, when the proportion of the infrared-absorbing dyes to theresin is adjusted., there can be obtained the optical sensor havingdesired characteristics as shown in FIGS. 4(a) and 4(b).

Next, a process of producing an optical sensor 40 according toEmbodiment 4 will be explained with reference to FIGS. 14.

In the step of forming the light-transmissive resin encapsulatingportion according to Embodiment 4, the substrate 1, having the pluralityof photodetectors 2 mounted thereon, as shown in FIG. 14(a) is set in alower mold 93, as shown in FIG. 14(b). Next, the substrate 1 is held andfixed between an upper mold 94 and the lower mold 93 under conditionswhere no resin leakage, substrate fracture or the like will occur, andthe transparent resin containing the infrared-absorbing dyes istransfer-molded. When the molds are separated from each other after theresin is cured, it is found that the photodetectors 21 and thesmall-gage metal wires 6 on the substrate 1 are encapsulated in thetransparent resin encapsulating portions 31 that also serves as theinfrared-blocking layer, as shown in FIG. 14(d). After that, thesubstrate is sectioned in the same manner as described above. Thus, theindividual optical sensors are completed as products.

In the optical sensor 40 according to Embodiment 4, the photodetector 2is entirely encapsulated in the transparent resin encapsulating portion31 having the function of absorbing infrared radiation, so that infraredradiation to enter the transparent resin encapsulating portion 31 fromevery angle can be blocked. Thus, the optical sensor has an improvedcharacteristic of blocking infrared radiation in addition to the sameeffect as obtained in Embodiment 1. In the process of producing theoptical sensor 40, the transparent resin encapsulating portion 31 andthe infrared-absorbing layer can be formed in one step without anincrease in the number of manufacturing steps.

EMBODIMENT 5

FIG. 15 is a front view in section of an optical sensor according toEmbodiment 5 of the present invention; and FIGS. 16 are a flowchartshowing the step of forming the resin encapsulating portion in theproduction of the optical sensor according to Embodiment 5.

In the optical sensor 50 according to Embodiment 5, aninfrared-absorbing layer 53 is formed on an outer surface of alight-transmissive resin encapsulating portion 51 and serves also as anouter resin portion. The light-transmissive resin encapsulating portion51 includes an inner resin portion 52 and an outer resin portion. Theinner resin portion 52 encapsulates the photodetector and made of aresin having insulating, light-transmissive and thermosettingproperties. The outer resin portion covers the inner resin portion 52.The outer resin portion is made of a mixture of two or more ofinfrared-absorbing dyes and a resin having light-transmissive andthermosetting properties and has the function of absorbing infraredradiation. Like reference numerals denote like parts in Embodiment 1 andexplanations thereon are omitted.

Next, a process of producing the optical sensor 50 according toEmbodiment 5 will be explained with reference to the flowchart of FIGS.16.

In the step of forming the light-transmissive resin encapsulatingportion according to Embodiment 5, the substrate 1 on which as shown inFIG. 16(a), the inner resin portions 22 are mounted to cover theplurality of photodetectors 2, respectively, is set in the lower mold 91as shown in FIG. 16(b). Then, a sheet resin 53′, containing two or moreinfrared-absorbing dyes, of B stage type, a type of resin having a highlight-transmittance and having been cured midway, is placed on the innerresin portions 52 on the substrate 1. After that, hot pressing with anupper mold 92 and the lower mold 91 is carried out, as shown in FIG.16(c). Thus, as shown in FIG. 16(d), there is obtained a molded resinpart wherein all the outer surfaces of the inner resin portion 52 arecovered with the infrared-absorbing layer 53. Then, the substrate issectioned to complete the individual optical sensors 20 as products.

In the optical sensor 50 according to Embodiment 5, the photodetector 2is entirely covered with the outer resin portion that serves also as theinfrared-absorbing layer 53 so that infrared radiation entering theouter resin portion (infrared-absorbing layer 53) from every angle canbe blocked. Thus, the optical sensor has an improved characteristic ofblocking infrared radiation in addition to the same effect as obtainedin Embodiment 1. In the process of producing the optical sensor 50, theinfrared-absorbing layer 53 and the outer resin portion can be formedsimultaneously in one step efficiently.

EMBODIMENT 6

FIG. 17 is a front view in section of an optical sensor according toEmbodiment 6 of the present invention; and FIGS. 18 are a flowchartshowing the step of forming the resin encapsulating portion in theproduction of the optical sensor according to Embodiment 6.

The optical sensor 60 according to Embodiment 5 includes, in addition tothe components recited in Embodiment 1, a light-shielding frame 62having a light-shielding property. The light-shielding frame 62 coversall the outer surfaces of the light-transmissive resin encapsulatingportion 11 except an outer surface thereof on the light-receivingsurface 2 a side of the photodetector 2. The light-shielding portion 62is made of, for example, a black-colored resin, shaped in a hollowsquare when viewed from the top, and is formed on the substrate 1 in aclose contact with the four outer surfaces of the light-transmissiveresin encapsulating portion 11. Like reference numerals denote likeparts in Embodiment 1 and explanations thereon are omitted.

A process of producing the optical sensor 60 according to Embodiment 6will be explained with reference to a flowchart of FIG. 18.

FIG. 18(a) shows the substrate 1 having the light-shielding frames 62provided around the plurality of photodetectors 2, respectively. Thephotodetectors 2 are mounted on the electrodes 3 arranged in theelectrode pattern 7 of FIG. 8. The light-shielding frames 62 are bondedin advance to the electrodes 3. In the step of forming thelight-transmissive resin encapsulating portion according to Embodiment6, the substrate 1 having the light-shielding portion 62 is set in alower mold 95 and then, a light-transmissive resin encapsulating portionformation resin 11′ is injected by using a dispenser 63 into eachlight-shielding frame 62 to the brim, as shown in FIG. 18(b). Afterthat, as shown in FIG. 18(c), the infrared-absorbing film as theinfrared-blocking layer 12 is placed on the light-shielding frames 62.Then, as shown in FIG. 18(d), the substrate 1 is held and fixed betweenan upper flat mold 96 and a lower mold 95 under conditions where noresin leakage, substrate fracture or the like will occur. Then, heatcuring is carried out by means of an oven or the like to obtain a moldedresin part as shown in FIG. 18(e). Then, the substrate is sectioned tocomplete the individual optical sensors 60 as products.

In the optical sensor 60 according to Embodiment 6, the light-shieldingframe 62 covers all the side surfaces of the photodetector 2 except thelight-receiving surface 2 a so that all light that enters thephotodetector 2 passes through the infrared-absorbing layer 12 to ensurethat the optical sensor has an improved characteristic of blockinginfrared radiation in addition to the same effect as obtained inEmbodiment 1. In the process of producing the optical sensor 60, thelight-shielding frame 62 serves as a frame for use in the formation thetransparent resin encapsulating portion 11 so that the need to use theupper mold illustrated in FIG. 7 of Embodiment 1 is eliminated.

EMBODIMENT 7

FIG. 19 is a front view in section of an optical sensor according toEmbodiment 7 of the present invention; and FIG. 20 is a flowchartshowing the step of forming the resin encapsulating portions in theproduction of the optical sensor according to Embodiment 7.

In Embodiment 7, the infrared-absorbing layer 12 as theinfrared-absorbing film in Embodiment 6 is replaced by aninfrared-absorbing layer 71 as a transparent-resin layer containinginfrared-absorbing dye(s). Like reference numerals denote like parts inEmbodiment 1 and explanations thereon are omitted.

A process of producing the optical sensor 70 according to Embodiment 7is as follows. First, the transparent resin 11′ having a heat curingproperty is injected into the light-shielding frame 62 in the samemanner as shown in FIG. 18(b) of Embodiment 6. Next, as shown in FIG.20(a), the substrate 1 is set in a printing stage 97; a metal mask 98having an aperture is set on the light-shielding frames 62; and a massof a light-transmissive resin 71′ having a heat curing property is puton one side of the metal mask 98. The resin 71′ is in the form of a geland contains infrared-absorbing dyes. After that, as shown in FIG.20(b), a squeegee 99 is moved so that the resin 71′ is poured into theaperture of the metal mask 98. Next, the resin 71′ is heat-cured bymeans of an oven without the mask 98 as shown in FIG. 20(c) to form thetransparent resin encapsulating portions 11 and the infrared-absorbinglayer 71. Then, the substrate is sectioned to complete the individualoptical sensors 70 as products.

In the optical sensor 70 according to Embodiment 7, the light-shieldingframe 62 covers all the side surfaces of the photodetector 2 except thelight-receiving surface 2 a so that all light that enters thephotodetector 2 passes through the infrared-absorbing layer 12 to ensurethat the optical sensor has an improved characteristic of blockinginfrared radiation in addition to the same effect as obtained inEmbodiment 1. In the process of producing the optical sensor 70, thelight-shielding frame 62 serves as a frame for use in the formation thetransparent resin encapsulating portion 11. Therefore, the need to usethe upper mold illustrated in FIG. 7 of Embodiment 1 and to use theupper flat mold 96 and the lower mold 95 that push theinfrared-absorbing film toward the substrate 1 in Embodiment 6 iseliminated.

EMBODIMENT 8

FIG. 21 is a front view in section of an optical sensor according toEmbodiment 8 of the present invention; and FIG. 22 is a flowchartshowing the step of forming the resin encapsulating portions in theproduction of the optical sensor according to Embodiment 8.

In Embodiment 8, a transparent resin encapsulating portion 81 containsinfrared-absorbing substances (as in the case with Embodiment 4 shown inFIG. 13) and the light-shielding frames 62 are provided around thetransparent resin encapsulating portions 81, respectively. Likereference numerals denote like parts in Embodiment 1 and explanationsthereon are omitted.

A process of producing an optical sensor 80 of Embodiment 8 is asfollows. In the step of forming the resin encapsulating portions, alight-transmissive-resin-encapsulating-portion formation resin 81′containing the infrared-absorbing dyes is injected by using a dispenser82 into each light-shielding frame 62 on the substrate 1 to the brim, asshown in FIG. 22(a) and FIG. 22(b). When resin 81′ is cured, the step isfinished. Then, the substrate is sectioned to complete the individualoptical sensors 70 as products.

In the optical sensor 70 according to Embodiment 80, the light-shieldingframe 62 covers all the side surfaces of the photodetector 2 except thelight-receiving surface 2 a so that all light that enters thephotodetector 2 passes through the infrared-absorbing layer 12 to ensurethat the optical sensor has an improved characteristic of blockinginfrared radiation in addition to the same effect as obtained inEmbodiment 1. In the process of producing the optical sensor 80, thelight-shielding frame 62 serves as a frame for use in the formation thetransparent resin encapsulating portion 11. Therefore, the need to usethe upper mold illustrated in FIG. 7 of Embodiment 1 is eliminated, andthe transparent resin encapsulating portion 81 and theinfrared-absorbing layer can be formed in the same step.

Meanwhile, in Embodiment 8, the resin encapsulating portions may beformed as shown in FIG. 23. First, the substrate 1 having thelight-shielding portions 62 as shown in FIG. 23(a) is set in the lowermold 95 as shown in FIG. 23(b). Next, a sheet resin 811, containing twoor more infrared-absorbing dyes, of B stage type, a type of transparentresin having been cured midway, is placed on the light-shielding frames62. After that, hot pressing with the upper mold 96 and the lower mold95 is carried out as shown in FIG. 23(c) to obtain a molded resin partas shown in FIG. 23 (d). Then, the substrate is sectioned to completethe individual sensors 70 as products.

Other Embodiments

1. Transfer molding in the production processes of Embodiments 1 and 4may be replaced by low-pressure molding. More specifically, the step offorming the resin encapsulating portion may comprise: interposing thesubstrate, having the plurality of photodetectors mounted thereon,between the upper mold and the lower mold, the upper mold having incorrespondence with the photodetectors the plurality of recesses to beused for formation of the light-transmissive resin encapsulatingportions; pouring a light-transmissive resin having a low viscosity byusing a dispenser through one injection port formed in one of the moldsso that the resin flows through a branched resin passageway into eachrecess inside the mold; and then allowing the resin to cure thereby toform the resin encapsulating portions (see FIGS. 7(a) to 7(d)). Thistype of formation step, owing to a wide choice of resins and low costsof the molds, is effective in producing small batches of a variety ofproducts.

2. The infrared-absorbing layer (infrared-absorbing film) used as theinfrared-blocking layer in Embodiments 1, 2 3 and 6 may be replaced byan infrared-reflecting layer (infrared radiation reflecting film).

3. The double-layer structure of the light-transmissive resinencapsulating portion with the outer resin portion covering the innerresin portion entirely in Embodiments 2 and 5 may be such that a lateralsurface of the inner resin portion is exposed to the outside.

According to the present invention, the function of absorbing orreflecting light in the infrared region can be incorporated in theoptical sensor without an increase in the number of components, so thatit is possible to save time and effort to incorporate, separately fromthe optical sensor, an infrared-blocking filter into electronicapparatus such as a personal digital assistant, making it possible tomanufacture electronic apparatus at a low cost without an increase inthe number of assembly steps. Also, by using the photodetector having apeak sensitivity in the visible-light region, control can be made on acriterion closer to the one applied by the human eye.

1. An optical sensor comprising: a substrate having an electrode; aphotodetector electrically connected to the electrode; and alight-transmissive resin encapsulating portion for encapsulating thephotodetector on the substrate, the optical sensor characterized byfurther comprising an infrared-blocking layer either inside thelight-transmissive resin encapsulating portion or on an outer surface ofthe light-transmissive resin encapsulating portion for blocking infraredradiation from the outside from reaching the photodetector.
 2. Anoptical sensor comprising: a substrate having an electrode; aphotodetector electrically connected to the electrode; and alight-transmissive resin encapsulating portion for encapsulating thephotodetector on the substrate, the optical sensor characterized in thatthe light-transmissive resin encapsulating portion contains aninfrared-absorbing substance.
 3. The optical sensor as set forth inclaim 1, wherein the infrared-blocking layer is formed on the outersurface of the light-transmissive resin encapsulating portion and iseither an infrared-absorbing layer containing an infrared-absorbingsubstance or an infrared-reflecting layer containing aninfrared-reflecting substance.
 4. The optical sensor as set forth inclaim 1, wherein the light-transmissive resin encapsulating portion hasan inner resin portion for encapsulating the photodetector and an outerresin portion for covering the inner resin portion and wherein theinfrared-blocking layer is interposed between the inner resin portionand the outer resin portion and is either an infrared-absorbing layercontaining an infrared-absorbing substance or an infrared-reflectinglayer containing an infrared-reflecting substance.
 5. The optical sensoras set forth in claim 2 wherein the infrared-absorbing substance is aphthalocyanine compound represented by the general formula (I):

wherein Zi (i=1-16) is SR₁, OR₂, NHR₃ or a halogen atom, wherein R₁, R₂and R₃ are a phenyl group which may have substituent(s), an aralkylgroup which may have substituent(s) or a C₁-C₂₀ alkyl group which mayhave substituent(s); and M is a nonmetal, a metal, a metallic oxide or ametallic halide.
 6. The optical sensor as set forth in claim 1, furthercomprising a light-shielding frame for covering all the outer surfacesof the light-transmissive resin encapsulating portion except an outersurface thereof on a light-receiving surface side of the photodetector.7. The optical sensor as set forth in claim 1, wherein the transmittanceof the light-transmissive resin encapsulating portion in thevisible-light region is substantially constant in the range of bluelight (450 nm) to red light (650 nm).
 8. The optical sensor as set forthin claim 2, containing two or more different infrared-absorbingsubstances.
 9. The optical sensor as set forth in claim 8, wherein thetwo or more different infrared-absorbing substances are phthalocyaninecompounds having absorption peaks at different infrared wavelengths. 10.The optical sensor as set forth in claim 9, wherein theinfrared-absorbing substances are phthalocyanine compounds havingabsorption peaks in the range of wavelengths of 750 nm to 1000 nm. 11.The optical sensor as set forth in claim 1, wherein the photodetector isa Si phototransistor.
 12. A process of producing an optical sensor,comprising the steps of: electrically connecting a photodetector to anelectrode provided on a substrate; and forming a light-transmissiveresin encapsulating portion on the substrate so that the photodetectoris entirely encapsulated in the light-transmissive resin encapsulatingportion, the process characterized in that the step of forming thelight-transmissive resin encapsulating portion includes the step offorming an infrared-blocking layer either inside the light-transmissiveresin encapsulating portion or on an outer surface of thelight-transmissive resin encapsulating portion for blocking infraredradiation from the outside from reaching the photodetector.
 13. Aprocess of producing an optical sensor, comprising the steps of:electrically connecting a photodetector to an electrode provided on asubstrate; and forming a light-transmissive resin encapsulating portionon the substrate so that the photodetector is entirely encapsulated inthe light-transmissive resin encapsulating portion, the processcharacterized in that in the step of forming the light-transmissiveresin encapsulating portion, the light-transmissive resin encapsulatingportion is formed of a transparent resin containing aninfrared-absorbing substance.
 14. The process of producing an opticalsensor as set forth in claim 12, wherein the step of forming theinfrared-blocking layer includes forming, on the outer surface of thelight-transmissive resin encapsulating portion, either aninfrared-absorbing layer containing an infrared-absorbing substance oran infrared-reflecting layer containing an infrared-reflectingsubstance.
 15. The process of producing an optical sensor as set forthin claim 12, wherein the step of forming the resin encapsulating portionincludes the steps of: forming an inner resin portion for encapsulatingthe photodetector; forming the infrared-blocking layer for covering anouter surface of the inner resin portion with either aninfrared-absorbing layer containing an infrared-absorbing substance oran infrared-reflecting layer containing an infrared-reflectingsubstance; and forming an outer resin portion for covering an outersurface of either the infrared-absorbing layer or theinfrared-reflecting layer.
 16. The process of producing an opticalsensor as set forth in claim 12, further comprising the step of forminga light-shielding frame for covering all the outer surface of thelight-transmissive resin encapsulating portion except an outer surfacethereof on a light-receiving surface side of the photodetector, the stepof forming the light-shielding frame being carried out before the stepof forming the resin encapsulating portion.
 17. The process of producingan optical sensor as set forth in claim 12, wherein the step of formingthe resin encapsulating portion comprises: holding the substrate, havinga plurality of said photodetectors mounted thereon, between an uppermold and a lower mold, the upper mold having, in correspondence with thephotodetectors, a plurality of recesses to be used for formation of thelight-transmissive resin encapsulating portion; pouring alight-transmissive resin into the recesses inside the mold; and thencuring the resin thereby to form the resin encapsulating portions.
 18. Alight-transmissive resin composition both for an optical sensor filterand for encapsulating a photodetector of an optical sensor, thelight-transmissive resin composition having an infrared radiationblockage function provided by addition of a plurality of phthalocyaninedyes as infrared-absorbing substances to a light-transmissive resin.